1. Field of the Invention
The present invention relates generally to a gas laser having a discharge channel in a discharge tube.
2. Description of the Related Art
A gas laser is disclosed in U.S. Pat. No. 3,753,144, showing examples of formats of gas lasers. In a first exemplary embodiment, a thin discharge tube and a separate gas return tube are provided. The first embodiment is not suitable for mounting mirrors on the discharge tube since differences in thermal expansion between the laser tube and the gas return line can cause misalignment of the mirror. On the other hand, another example shows the laser discharge capillary and the gas return channels accommodated in a relatively wide ceramic tube. Such arrangement generally exhibits a poor heat transfer characteristic from the capillary to the outside wall. Therefore, complex measures must be undertaken for heat dissipation.